Ophrydium

On Thursday I went up Ben Venue. Close to the summit (which can be seen in this picture) there is a small pond which sometimes dries out.

Below is a photo of the pond taken early in the year, looking the other way, towards the trig point which is at the second top of the hill.

In this small pond I noticed some greenish masses and I thought this would be something to interest Fred so I tried to collect some. This proved difficult, as it kept slipping out of the collecting tube, so I used a bag instead.

Under the microscope, this turned out to be tiny protozoa, each containing green algae. We identified them as Ophrydium, though this usually grows in a much more defined greenish spherical jelly-like lumps. Maybe this was an old colony.

The creatures have tiny beating hairs at the front...

...and a long point at the rear.

Our videos:

See also:

Green jelly balls of Ophrydium versatile

Droplet: amateur microscopy of the Protozoa

Protist Information Server

Size dependence of composition, photosynthesis and growth in the colony forming freshwater ciliate, Ophrydium versatile. Freshwater Biol. 31: 121-130

Some notes on an uncommon colonial peritrichous protozoon, Ophrydium versatile (O.F.M.). E.D. Hollowday. Microscopy 32, July-December 1975

Rotifer

The tube-building sessile rotifer, Floscularia ringens

A rotifer is a microscopic animal that is mainly found in fresh water. There are about 600 species found in the British Isles.

Tube-building rotifers are difficult to observe, as they withdraw into their tube with the slightest vibrations. This makes it difficult to take still photos, and more so to take a video clip.


This shows the rotifer causing currents in the water as it draws food into its mouth.

When the eggs of this rotifer hatch, they are free-swimming until they find the leaf of a water plant. Each species of rotifer uses a different type of plant. Some species will only attach themselves to the upper or lower surface of the leaf. The animal builds its protecting tube from debris it collects and the waste from its digestive system. The pattern of the pellets the tube is made from is specific to each species of sessile rotifer. Once the rotifer attaches itself to its chosen leaf, it never moves from this position.

There is more information about rotifers on our site.

Midge larvae

A few days ago I discovered what appeared to be eggs in a mass of jelly about 2cm long in a tray of water in our garden.

The eggs appeared to be arranged spirally within the jelly.

On examination under the microscope, we could see small creatures inside the eggs.

Three days later, these had hatched out as small larvae.

These appear to be the larvae of Chironomids, or non-biting midges. We'll watch to see how they develop.

Addition to previous blog entry:

Last Saturday I found more star jelly, high up on a Scottish mountain.

More algae

Today we have been looking at some water we collected from a ditch yesterday. It was full of various sorts of algae (primative plants). The most frequent in the sample was this rather beautiful feathery-looking one (Draparnaldia sp.), seen here under the microscope.

Very long, fine hairs can be seen extending from the ends of the branches.

Among the strands of this alga were numerous desmids, such as the large round green one in this picture (Micrasterias sp.), diatoms, and other small algae.

Here is a larger picture of Micrasterias, showing its structure.

For more desmids, see also 28 August 2008.

Desmids

Last Saturday, while I was out walking in the hills to the south of Glasgow, I collected a sample of water from a boggy area for Fred to examine under his microscope. The water looked like green soup.

Under the microscope, we found that it was full of desmids. These are single-celled green algae. They can be seen among the strands of a filamentous alga in this image.

Algae are primative plants and include the seaweeds.